Lutein

Figure 1. The chemical structure of Lutein.

Lutein is a xanthophyll (i.e. yellow pigment in plants) and one of 600 known naturally occurring carotenoids (of which Beta-Carotene is a member of). Lutein is synthesized only by plants and cannot be produced in the human body. Lutein is related to Beta-Carotene and Vitamin A.

Lutein is one of two major carotenoids found in the human eye (the other being Zeaxanthin). Lutein is thought to function as a light filter, absorbing blue light and protecting the eye tissues from sunlight damage. In the human retina, Lutein is absorbed from blood specifically into the macula lutea (or macula).

Like other xanthophylls, Lutein is found in high quantities in green leafy vegetables such as spinach, kale and yellow carrots. Some other food sources for Lutein include:

• Egg yolk
• Orange pepper
• Kiwi fruit
• Grapes
• Zucchini
• Squash
• Broccoli
• Lettuce
• Parsley
• Basil
• Leeks
• Peas
• Corn
• Wheat
• Pistachios

As a dietary supplement, Lutein is commonly promoted to help with eye diseases, including cataracts and age-related macular degeneration (or AMD, a disease that leads to vision loss in older adults), by suppressing inflammation and defending against oxidative stress (Lutein is a carotenoid, thus functions as an antioxidant). Lutein is best absorbed by the human body when it is taken with food that has a high fat content (because lipoproteins are the main transport vehicle for Lutein).

Lutein is isomeric (i.e. molecularly equivalent) with Zeaxanthin, differing only in the placement of one double bond.